Method for detecting pesticide residues by using magnetic relaxation time sensor based on quantity and state change of nano magnetic particles

A nano-magnetic particle and state change technology, which is applied in the direction of immunodiagnostic reagent carriers, instruments, and measuring devices of magnetic particles, can solve the problem of changing the number of magnetic particles, and achieve the effects of simple operation, fast detection speed, and simple pretreatment

Active Publication Date: 2020-04-14
WUHAN ACADEMY OF AGRI SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, small molecule chemicals such as pesticides have only one antibody binding site, which cannot effectively cause changes in the number of magnetic particles. Therefore, other amplification methods are needed to use magnetic relaxation time immunosensors for trace amounts of pesticide residue small molecules. highly sensitive detection of

Method used

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  • Method for detecting pesticide residues by using magnetic relaxation time sensor based on quantity and state change of nano magnetic particles
  • Method for detecting pesticide residues by using magnetic relaxation time sensor based on quantity and state change of nano magnetic particles
  • Method for detecting pesticide residues by using magnetic relaxation time sensor based on quantity and state change of nano magnetic particles

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Example 1. Construction of the magnetic relaxation immunosensor

[0047] (1)Azide-MNP 30 Preparation of conjugates

[0048] 100 μL of 15-azido-4,7,10,13-tetraoxopentadecanoic acid-N-succinimidyl ester (Azide-PEG 4 -NHS ester) solution (1mg / mL) was added to 200μL NH 2 -MNP 30 solution (2.5 mg / mL), stirred slowly at room temperature for 1 hour. After the reaction was completed, magnetic separation was performed at 4°C for 12 hours, and the supernatant was removed to obtain Azide-MNP 30 The conjugate was then resuspended in 500 μL of PBST (pH=7.4, 0.01 M, containing 0.05% Tween 20), and this process was repeated three times. Finally, Azide-MNP 30 The conjugate was resuspended in 100 μL of PBS solution (pH=7.4, 0.01 M), and stored at 4° C. for future use.

[0049] In this embodiment, the amount of Azide in the coupling process is optimized, the specific method is as follows: take different quality Azide-PEG 4 -NHS with 1mg MNP 30 Coupled, the resulting Azide-MNP 3...

Embodiment 2

[0061] Embodiment 2. Comparison of the sensitivity of the magnetic relaxation immunosensor with the traditional magnetic relaxation time sensor

[0062] According to embodiment 1, respectively use traditional MRS ( Figure 7 A), MRS based on the change of the number of magnetic particles ( Figure 7 D), and MRS based on the number and state changes of magnetic particles ( Figure 7 G) Detection of gradient concentrations of chlorpyrifos. The specific methods are: (1) Traditional MRS: antibody coupling on magnetic particles (MNP 30 -Ab), and coupled to another magnetic particle complete antigen (MNP 30 -BSA-chlorpyrifos), mix 100 μL of different concentrations of chlorpyrifos solution with 100 μL of MNP 30 -BSA-chlorpyrifos solution, 100 μL MNP 30 -Ab conjugates are mixed, and a competitive immune reaction occurs, causing the aggregation of magnetic particles (MNP 30 -Ab-chlorpyrifos-BSA-MNP 30 , state change), thus causing T 2 value changes. (2) MRS based on the chang...

Embodiment 3

[0064] Example 3. Research on the Specificity and Recovery of the Magnetic Relaxation Immunosensor

[0065] (1) In the specificity test, four chlorpyrifos analogues, dimethoate, triazophos, glyphosate, and chlorpyrifos, were added to measure the specificity of the sensor for detecting chlorpyrifos, so as to verify the specificity of the sensor. Wherein, the concentration of chlorpyrifos is 10 ng / mL, and the concentration of these analogues is 100 ng / mL. Such as Figure 8 As shown, only chlorpyrifos can cause T 2 Significant changes in the value, other analogues have a negligible effect on the magnetic signal.

[0066] (2) The recovery rate was studied by the standard addition method, that is, different concentrations of chlorpyrifos (0.5, 1, 5, 10, 50 and 100 ng / mL) were added to the blank apple sample, and then the sensor was used for determination. As shown in Table 1, the recovery rate of chlorpyrifos detection (76%-119%) also shows the accuracy of the method.

[0067] ...

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Abstract

The invention discloses a method for changing the number and state of nano magnetic particles based on a biological orthogonal reaction for detecting pesticide residues. According to the method, the number and the aggregation state of the nano magnetic particles are changed simultaneously on the basis of the cascade biological orthogonal reaction of diphenyl cyclooctyne and azide, controllable adjustment of the number and the state of the magnetic nano particles is realized, and magnetic signal cascade amplification is performed by organic combination of diphenyl cyclooctyne and azide, so thatthe accuracy and the sensitivity of pesticide residue detection are improved.

Description

technical field [0001] The invention belongs to the technical field of food safety detection, and in particular relates to a method for detecting pesticide residues with a magnetic relaxation time sensor based on the number and state changes of nano magnetic particles. Background technique [0002] Food safety is related to the health of the general public and is an important livelihood project. Pesticide residues in food are an important food safety issue that endangers human health. Due to illegal use of highly toxic pesticides, increased resistance of diseases and insect pests, improper use of pesticides and other reasons, pesticide residues often exceed the standard, and pesticide residues are extremely harmful to human health, causing acute or chronic poisoning, reducing human immunity, and causing cancer. Teratogenic and mutagenic, and even cause the death of individuals. In view of the huge harm caused by pesticide residues to health, reducing and rationally using pe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N33/577G01N33/543
CPCG01N33/577G01N33/54326G01N2430/00G01N2446/00
Inventor 陈翊平董永贞曾令文
Owner WUHAN ACADEMY OF AGRI SCI
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